Factor XI (Plasma Thromboplastin Antecedent)

<< previous

Afibrinogenemia is the complete absence of fibrinogen. Hypofibrinogenemia is a low level of fibrinogen—less than 100mg in 1dL of blood. Both conditions are inherited in an autosomal fashion and can affect males and females.

The severity of the disorder is related to the amount of fibrinogen. Afibrinogenemia is usually discovered in newborns and can cause bleeding from the umbilical cord, genitourinary tract, or central nervous system. People with hypofibrinogenemia may have little, moderate, or severe bleeding.

Prothrombin is a vitamin K-dependent proenzyme that functions in coagulation. There are two types of this deficiency, a congenital version called hypoprothrombinemia, and an acquired version called dyspothrombinemia.
A life-long bleeding disorder when congenital, it's extremely rare. In fact, only 30 cases of this hereditary clotting factor defect have been identified in the whole world.

Acquired factor II deficiency is more common. It results from vitamin K deficiency, severe liver disease, and therapeutic use of anticoagulant drugs. Risk factors for vitamin K deficiency are prolonged use of antibiotics, bile duct obstruction, and intestinal malabsorption (inadequate absorption of nutrients from the intestinal tract) disorders. Some newborns are born with vitamin K deficiency.

If it is caused by liver disease, the outcome depends on the control of the liver problem. Vitamin K administration will correct vitamin K deficiency.

Either form may lead to severe bruising, excessive menstrual bleeding, postoperative hemorrhage, or occasionally muscle bleeds.

A congenital factor II deficiency is a very rare inherited disorder that results in deficient blood clotting. The disorder is not sex-linked as is hemophilia. It affects both males and females with equal frequency. It is autosomal recessive, which means if the clotting defect is inherited from a parent, the child will be a genetic carrier of the condition, but may or may not have symptoms. A family history of bleeding disorder is a risk factor.

This deficit was identified in Norway in 1943. Since then about 150 cases have been reported, occurring in both men and women. The exact frequency of this rare disorder is unknown, but is estimated to be one per million.

The role of factor V is to accelerate the activity of thrombin. When levels of factor V are low, blood clotting is delayed or it progresses slowly. People with this deficiency may have occasional nosebleeds, excessive menstrual bleeding, and bruising, although many have no symptoms. The first sign of this condition may be bleeding following surgery.

In this disorder, bleeding ranges from mild to severe. The disease is similar to hemophilia, except bleeding into joints is uncommon. Bleeding can occur almost anywhere in the body, and death from hemorrhage has occurred with this disorder. Excessive bleeding with menstrual periods and postpartum hemorrhage occurs frequently.

A family history of a bleeding disorder is a risk factor. Men and women are affected equally.

The probable outcome is good with proper diagnosis and treatment.

This extremely rare disorder can be inherited or acquired by persons without hemophilia who take Coumadin, a drug used to inhibit blood clotting.

In this disorder, bleeding can vary from mild to severe within the same person over time. Bleeding doesn't always correspond with the severity of the deficiency shown in blood tests. A history of bleeding may occur in infancy or childhood.

Gastrointestinal and central nervous system bleeding can also occur.
This disorder occurs in one in 500,000 males and females. Congenital factor VII deficiency should be distinguished from acquired factor VII deficiency that may result from liver disease, vitamin K deficiency, or other malabsorption conditions.

When levels of the factor are less than 1% of normal, bleeding can be severe. The trauma of birth may cause bleeding in the head of a newborn. Circumcision may cause prolonged bleeding. Children and adults may suffer bleeding from nose, gums, or gastrointestinal tract, and women may suffer excessive menstrual bleeding.
The probable outcome is good with proper treatment.

Factor X deficiency ranks with factor II as one of the rarest inherited clotting disorders, with only about 50 reported cases. It is a vitamin K-dependent clotting factor in the blood. It was first discovered in a man named Stuart from the mountains of North Carolina. He was originally thought to have factor VII deficiency, but then a woman named Prower was found to have a similar clotting abnormality and the new factor X was discovered.

In factor X disorder, bleeding ranges from mild to severe. Severity ranges on the level of factor X clotting activity. Women may have severe menstrual bleeding and postpartum hemorrhage. The incidence ranges from 1 out of 500,000 to 1 out of 1,000,000 people. Newborns may present with prolonged bleeding after circumcision. People with factor activity that is less than 1% of normal are susceptible to severe bleeding. Those with 10% or more are only mildly affected.

Some cases are due to reduced or absent synthesis of the molecule. In other cases, the number of molecules is normal, but they don't work properly. Several genetic variations of factor X deficiency of varying severity have been described.

Even more uncommon than the congenital form of factor X deficiency is the acquired form. It has occasionally developed in patients with liver disease, vitamin K deficiency, amyloidosis, myeloma, leprosy, mycoplasma infections, various tumors and exposure to the fungicide methylbromide.

Factor X levels have been shown to increase during pregnancy, but aggressive replacement therapy is needed for women in pregnancy for women with a severe deficiency and a history of early and recurrent miscarriage.

Factor XI deficiency is a very rare bleeding disorder, occurring in an estimated one in 100,000 Americans. It has more variable bleeding tendencies than hemophilia A and B and people with the disorder usually don't bleed into joints and muscles, as in hemophilia. The disorder is usually only mild, and typically provoked by surgery.
Factor XI is a protein that helps blood clot, and is activated by thrombin. Deficiencies occur rarely, and in all racial groups, but it is particularly common to Ashkenazi Jews. These are primarily Jews of eastern European ancestry, and the relationship is presumably because intermarriage within this closed group, generation after generation, allowed the defective gene to surface more frequently.

In the U.S., most cases are found in New York and Los Angeles. Approximately 200 cases of factor XI deficiency have been reported since it was identified in 1953. Ever since, the deficiency has been a puzzle, because of its variable bleeding symptoms in different patients—even at different points in their lives and with different injuries and surgeries.

Three different genetic mutations have been identified, and a person's particular mix of these influences their bleeding tendencies.

Asians are born with the deficiency more than any other ethnic group.

The deficiency is somewhat of a medical mystery. It does not cause abnormal bleeding, even with major surgical procedures. The hallmark of severe factor XII deficiency is prolonged APTT—usually more than 100 seconds—in a patient with no history of bleeding.

The outcome is expected to be good even without treatment.

This is perhaps the rarest of all factor deficiencies, affecting just one in several million. A hallmark of this rare inherited deficiency is poor wound healing and abnormal scar formation. The reason is that factor XIII—fibrin stabilization factor—is necessary for clot formation and wound healing.

Factor XIII is responsible for clot stabilization and cross linking of the fibrin polymer in blood. A clot will form in the absence of factor XIII, but it will be unstable.

Factor XIII deficiency is a severe bleeding disorder usually associated with trauma. Typically, it's discovered in newly-born babies who suffer recurrent bleeding from the umbilical stump and hemorrhages after circumcision.

Severely affected patients have a high incidence of intracranial hemorrhage with little or no trauma. Affected women often experience spontaneous abortion unless treated with plasma replacement therapy. Bleeding in surgery is not excessive, but delayed bleeding can occur.

Click on factors to see description